LeetCode Tracker - Serverless Version

A serverless LeetCode practice tracker built with Next.js and deployed on Vercel.

Features

• Fetches recent LeetCode submissions
• Randomly selects questions for review
• Sends email reminders via EmailJS
• Tracks revision counts
• Automated daily updates via Vercel Cron Jobs

Setup

1. Install dependencies:

   npm install

2. Set up environment variables:

   • Copy .env.example to .env.local
   • Add your database credentials (Vercel Postgres, Neon, or Supabase)
   • Add your EmailJS credentials
   • Generate secure tokens for SECRET_TOKEN and CRON_SECRET

3. Create the database table:

   CREATE TABLE questions (
     id SERIAL PRIMARY KEY,
     url VARCHAR(255) UNIQUE NOT NULL,
     numberofrevision INTEGER DEFAULT 0,
     last_sent_date TIMESTAMP
   );

4. Create a Redis cache using Vercel. Vercel Marketplace provides easy integration with Upstash Redis for Nextjs. Store the Redis Secrets in your .env file.

5. Deploy the project on Vercel. Once you receive the project URL from Vercel, update the baseurl in api/cron/daily-update/route.ts with the new URL, then redeploy the project on Vercel.

EmailJS Template

Use the following variables in your EmailJS template:

<div
   style="
      max-width: 600px;
      margin: auto;
      font-family: Arial, sans-serif;
      color: #2d3748;
      background: #ffffff;
      border-radius: 8px;
      padding: 24px;
      border: 1px solid #e5e7eb;
      line-height: 1.6;
   "
>
   <!-- Header -->
   <div
      style="
         text-align: center;
         padding-bottom: 16px;
         border-bottom: 1px solid #e5e7eb;
      "
   >
      <h2 style="margin: 0; font-size: 22px; color: #1a202c">
         Daily LeetCode Revision
      </h2>
   </div>

   <!-- Body -->
   <div style="padding: 20px 0">
      <p style="margin: 0 0 12px">Hello Leetcoder,</p>
      <p style="margin: 0 0 20px">
         Here are your two questions to review today:
      </p>

      <ol style="padding-left: 20px; margin: 0 0 20px">
         <li style="margin-bottom: 12px">
            <strong>Question {{first_question_id}}</strong><br />
            <a
               href="{{first_question_url}}"
               target="_blank"
               style="color: #3182ce; text-decoration: none"
               >{{first_question_url}}</a
            >
         </li>
         <li>
            <strong>Question {{second_question_id}}</strong><br />
            <a
               href="{{second_question_url}}"
               target="_blank"
               style="color: #3182ce; text-decoration: none"
               >{{second_question_url}}</a
            >
         </li>
      </ol>

      <p style="margin: 20px 0">
         Keep practicing daily — steady progress builds mastery.
      </p>
   </div>

   <!-- Footer -->
   <div
      style="
         font-size: 12px;
         color: #718096;
         text-align: center;
         border-top: 1px solid #e5e7eb;
         padding-top: 12px;
      "
   >
      <p style="margin: 4px 0">Made with ❤️ by contributors</p>
      <p style="margin: 4px 0">
         <a
            href="https://github.com/bismansahni/Leetcode-Tracker-Reminder"
            target="_blank"
            style="color: #3182ce; text-decoration: none"
         >
            View on GitHub
         </a>
      </p>
   </div>
</div>

Deploy to Vercel

1. Push to GitHub
2. Import project to Vercel
3. Add environment variables in Vercel dashboard
4. Deploy

Cron Job Configuration

The daily update runs automatically at 9:00 AM UTC. To change the schedule, edit vercel.json:

{
  "crons": [
    {
      "path": "/api/cron/daily-update",
      "schedule": "0 9 * * *"  // Cron expression
    }
  ]
}

API Endpoints

• GET /api/hit-main?token=YOUR_TOKEN - Fetch questions and send email
• GET /api/commit-question?token=YOUR_TOKEN&id1=X&id2=Y - Update revision count
• GET /api/cron/daily-update - Automated endpoint (called by Vercel Cron)

Database Options

Vercel Postgres (Recommended)

• Automatic connection pooling
• Built-in with Vercel
• Use @vercel/postgres package

Neon or Supabase

• Update lib/db.ts to use their connection strings
• Both support serverless environments

Migration from Flask

1. Database remains the same (PostgreSQL)
2. Endpoints map directly:
   • /HitMain → /api/hit-main
   • /CommitQuestion → /api/commit-question
3. Cron job replaces manual scheduling
4. Environment variables stay similar

Dashboard Visualizations

Enable the optional analytics dashboard with NEXT_PUBLIC_ANALYTICS_FLAG=1.

Question Count Analytics

Revision-Based Analytics

Progress Analytics